Observation Impact and Forecast Sensitivity of Enhanced AMVs Using WRF for 2008 Typhoon Period

The purpose of this study is to evaluate the observation impact and forecast sensitivity to observations (FSO) of enhanced atmospheric motion vector (AMV) data by using Weather Research and Forecasting model (WRFv3.3) during typhoon season (September 2008) of East Asian region. Instead of performing observing system experiment (OSE), the adjoint model was used to efficiently calculate the effects of AMV observations on forecasts. The center of domain is located in 25 N 125 E with 235 by 197 horizontal grid points and 41 vertical layers. The model top is 50hPa. Spin-up was carried out from August 25th to 31st and the evaluation is made for whole September for three different typhoons (Sinlaku (0813), Hagupit (0814), and Jangmi (0815)). Two experiments were performed in the study. The first experiment is used as a control by assimilating conventional observations at every 00, 06, 12, 18 UTC, whereas the rapid scan (RS) AMV data were added in assimilation at every 03, 09, 15, 21 UTC for the second experiment. The preliminary results showed that Sound data have the most positive impact followed by satellite data, SYNOP and QSCAT. More detailed results will be presented in the conference.

Keywords: Forecast sensitivity to observation, observation impact, forecast error, enhanced atmospheric motion vector

Acknowledgements: This study was supported by the Korea Meteorological Administration Research and Development Program under Grant CATER 2012-2030. We appreciate Chris Velden and Brett Hoover for providing enhanced AMV data for this study.